ERROR###ERROR###ERROR###ERROR###ERROR###ERROR###ERRORW:Failed to fetch http://ppa.launchpad.net/venerix/blug/ubuntu/dists/quantal/main/source/Sources 404 Not Found, W:Failed to fetch http://ppa.launchpad.net/venerix/blug/ubuntu/dists/quantal/main/binary-amd64/Packages 404 Not Found, W:Failed to fetch http://ppa.launchpad.net/venerix/blug/ubuntu/dists/quantal/main/binary-i386/Packages 404 Not Found, E:Some index files failed to download. They have been ignored, or old ones used instead.

This error message does not mean that you experience any problem updating Linux Mint 14 at all.All that this error message tells is that a particular PPA repository cannot be contacted.Going to this address, http://ppa.launchpad.net/venerix/, I see a subfolder blug-deletedppa, but no more folder blug. This seems to suggest that indeed the PPA does no longer exist.Visit this page: https://launchpad.net/+search?field.text=venerix and search for venerix. Find out whether the PPA repository has just been moved to a different location or whether it has stopped existing.Correct the list of your repositories accordingly.